In general, toothpaste widely used at home is contained in a soft tube type dispenser. Since the dispenser is squeezed to dispense a dose of the toothpaste, the tube is crushed according to the pushed position. Also, since contents are not wholly discharged, the contents are left on an inner surface of the tube.
In order to solve the above problems, a piston type airtight dispenser is disclosed in Korean Utility Model No. 0261356. The piston type airtight dispenser includes a cylinder having a plunger coupled to an inner upper end portion of a tubular body and airtightly moving downward by pressure applied from an upper portion; a lower plate airtightly coupled to a lower end portion of the cylinder and having a through-hole formed at a center portion and a working hole of a diameter larger than that of the through-hole at a lower end; an upper plate coupled to the upper end portion of the cylinder and having a plurality of suck holes; a dispensing plug engaged to the lower end portion of the working hole of the lower plate and having a dispensing hole formed at a center thereof; a check valve installed between the lower plate and the dispensing plug and opening the dispensing hole of the dispensing plug if the pressure is applied to the upper portion of the plunger in the cylinder while closing the dispensing hole if the pressure applied to the upper portion of the plunger is released; and a piston positioned on the upper portion of the plunger of the cylinder and moving the plunger downwards.
The piston includes a disc-shaped pressing plate closely contacting the inner periphery of the cylinder at the upper portion of the plunger and having an engaging hole with an inclined pressing surface formed at a center thereof; a pushing bar having at a lower end portion thereof a boss engaged with the engaging hole of the pressing plate, a pressing portion contacting the inclined pressing surface, and at an upper end portion thereof a pressing portion, a stepped portion being formed on a middle portion of a body; a restoring plate inserted in a body of the pushing bar and hooked in the stepped portion of the bottom of the body and having a plurality of through-holes; and a tension spring having one end engaged with a portion of the upper portion of the cylinder and the other end urging the restoring plate upwardly.
With the construction, when a user pushes down the pushing bar, the plunger is downwardly pushed by the pneumatic pressure to generate pressure. The check valve opens the dispensing hole of the dispensing plug in accordance with the pressure, so that the contents are dispensed outwardly from the dispenser through the dispensing hole.
In the piston type airtight dispenser, however, it is very difficult to employ the piston separated from the cylinder in other cylinder since the piston is integrally formed with the cylinder. Consequently, it is troublesome to disassemble the piston from the cylinder, in order to mount the piston in other cylinder having no piston.
More specifically, in order to make the use of the piston in other cylinder, firstly, after the upper plate is detached from the cylinder, the pressing bar integrally engaged with the restoring plate and the pressing plate is pulled up, and then the tension spring is disassembled from the upper portion of the cylinder, thereby disengaging the piston from the cylinder.
Consequently, the operation of separating the piston from the cylinder is complicated. Also, since the pushing bar and the tension spring which constitute the piston are separated from each other, the tension spring separated from the cylinder may be lost.
As described above, it is not easy to disengage the piston from the cylinder. Since most of the users do not effectively make the use of the piston in other cylinder, it is not effective in view of the recycle of resources. In case the dispenser is constructed not to be refilled with contents, the user should throw away the used dispenser, and then purchase a new dispenser having a piston, which imposes expenses on the user.
In addition, since the piston is constituted of many parts, such as the upper plate, the restoring plate, the pressing plate, the tension spring, and the like, the construction thereof is very complicated, thereby increasing its manufacturing cost.